Installation & Power Requirements

For correct operation of the 3200 it must be powered from an unprotected (ie. no RCD trip) supply. This is because the 3200 will pass current down the Earth conductor when performing tests and therefore trip any protection device present - FOR THIS REASON IT IS ESSENTIAL THAT THE 3200 IS PROPERLY EARTHED.

 It is also necessary that for correct operation the Phase (Live) and Phase (Neutral) MUST be connected round the correct way (some plugs used in non-UK countries can be connected either way round, therefore this check is necessary). There should only be a small voltage between Phase (Neutral) and Phase (Earth).

To keep the LOOP impedance value to a minimum, the mains input to the 3200 is of a direct cable type. This avoids any introduction of unnecessary impedance.

It is desirable that the 3200 is connected to a supply point with low LOOP impedance as this will limit the lowest value available LOOP impedance from the 3200 using as good a quality outlet (contact wise) as possible.

If an unprotected supply is not available, use of an Isolation Transformer can be employed, however this will increase the lowest LOOP impedance available.

Connection of the isolation transformer should be as detailed below :

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Prospective Short Circuit Current Testing Using the 3200

Some LOOP / Installation testers have the capability to measure PSCC (Prospective Short Circuit Current) which is the largest Prospective Fault Current (PFC) which could flow.

This current is limited by the LOOP resistance of the circuit and can be calculated for either :

• Phase (Live) to Earth
• Phase (Live) to Phase (Neutral)

The more usual is Phase (Live) to Phase (Neutral)

The LOOP / Installation testers calculate this measurement from the measured LOOP resistance using the formula :

                         Nominal supply voltage

    PSCC =      -----------------------------------                       

                         LOOP Resistance

This function can be calibrated with the 3200 by using the LOOP function

The standard lead supplied with the 3200 will enable you to simulate Phase (Live) to Earth PSCC. If Phase (Live) to Phase (Neutral) PSCC testing is required, the lead detailed below will need to be made :

To calibrate, compare the reading obtained on the Installation tester with the value calculated from the formula above using the LOOP impedance displayed on the 3200.

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